Randomized Phase II Trial of Amrubicin Plus Irinotecan Versus Cisplatin Plus Irinotecan in Chemo-naïve Patients With Extensive-Disease Small-Cell Lung Cancer: Results of the Japan Multinational Trial Organization (JMTO) LC 08-01

Abstract

Background: We conducted a randomize phase II study to evaluate the efficacy and safety of topoisomerase II inhibitor amrubicin plus topoisomerase I inhibitor irinotecan (AI) compared with cisplatin plus irinotecan (PI) as first-line therapy in patients with extensive-disease (ED) small-cell lung cancer (SCLC).

Patients and methods: Chemo-naïve patients with pathologically proven ED-SCLC (including limited disease (LD) SCLC with malignant effusion) were enrolled. Patients were randomized 1:1 to receive either AI (amrubicin 90mg/m² on day 1 and irinotecan 50mg/m² on days 1 and 8 of a 21-day cycle) or PI (cisplatin 60mg/m² on day 1 and irinotecan 60mg/m² on days 1, 8 and 15 of a 28-day cycle). The primary endpoint was overall survival proportion at 1 year.

Results: A total of 100 patients were randomly assigned to AI (n = 50) or to PI (n = 50). The 1-year overall survival proportions were 68.0% (95% confidence interval (CI): 56.2-82.2%) for AI and 59.2% (46.9-74.7%) for PI (1-sided P = .18). Median survival time was 14.8 months for AI and 13.5 months for PI with a hazard ratio (HR) of 0.618 (0.398-0.961, stratified log-rank test P = .031). Median progression-free survival time was 4.8 months for AI and 5.4 months for PI (stratified log-rank test, P = .54). Objective response rate was 70.0% (55.4-82.1%) for AI and 55.1% (40.2-69.3%) for PI (Fisher exact test, P = .15). There was no significant difference in hematological toxicity, whereas rates of vomiting, loss of appetite, diarrhea, and elevated serum creatinine are more frequent in PI. Interstitial lung disease (Grade 2 or 3) developed in 5 patients in AI and in 1 patient in PI. There was no treatment-related death.

Conclusion: Although the study did not meet its primary endpoint, AI showed promising efficacy and good tolerability in chemo-naïve patients with ED-SCLC.

Keywords: Amrubicin; Chemo-naïve; Extensive-disease; Irinotecan; Small-cell lung cancer.